Analysis of the Overall Reliability Slender Concrete Columns

2017 ◽  
Vol 259 ◽  
pp. 203-208
Author(s):  
Vladimír Benko ◽  
Tomas Gúcky ◽  
Adrián Valašík
Keyword(s):  
Concrete Columns ◽  
Design Methods ◽  
Second Order ◽  
Order Effects ◽  
Design Strength ◽  
Order Analysis ◽  
Non Linear ◽  
Buckling Failure ◽  
Overall Reliability ◽  
General Method

Standard for designing of concrete structures STN EN 1992-1-1 offers three methods of analysis of second order effects with axial load. Namely, a general method based on non-linear second order analysis and two simplified methods: Method based on nominal stiffness and method based on nominal curvature. According to three series of the experiments of slender concrete columns and after calibration of the non-linear calculations, the authors in following paper compare the global reliability of above mentioned design methods with parametric study. According to executed research is possible to say that the differences in reliability of the design methods are considerable in several cases of the slender concrete columns design.The experiments were executed in the Central laboratory of Faculty of Civil Engineering STU in Bratislava in cooperation with company STRABAG ltd. The series of columns differed only in strength class of concrete (C45/55 for S1, C70/85 for S2, C80/95 for S3) and each series included six tested samples. The geometry and reinforcement of the columns as well as the initial eccentricity of the axial force were design so, that the buckling failure of the columns occurred earlier than the design strength of materials in the most stressed cross-section ran out.

scholarly journals ANALYSIS OF THE GLOBAL AND LOCAL IMPERFECTION OF STRUCTURAL MEMBERS AND FRAMES

2019 ◽  
Vol 25 (8) ◽  
pp. 805-818 ◽  
Author(s):  
Charlotte Mercier ◽  
Abdelouahab Khelil ◽  
Ali Khamisi ◽  
Firas Al Mahmoud ◽  
Rémi Boissiere ◽  
...  
Keyword(s):  
Second Order ◽  
Structural Defects ◽  
Order Effects ◽  
Structural Members ◽  
Buckling Mode ◽  
New Approach ◽  
Order Analysis ◽  
Main Challenge ◽  
Buckling Failure ◽  
Global And Local

Stresses of a structure are determined with a first or a second order analysis. The choice of the method is guided by the potential influence of the structure’s deformation. In general, considering their low rigidity with regard to those of buildings, scaffolding and shoring structures quickly reach buckling failure. Imperfections, such as structural defects or residual stresses, generate significant second order effects which have to be taken into account. The main challenge is to define these imperfections and to include them appropriately in the calculations. The present study suggests a new approach to define all the structure’s imperfections as a unique imperfection, based on the shape of elastic critical buckling mode of the structure. This study proposes a method allowing to determine the equation of the elastic critical buckling mode from the eigenvectors of the second order analysis of the structure. Subsequently, a comparative study of bending moments of different structures calculated according to current Eurocode 3 or 9 methods or according to the new method is performed. The obtained results prove the performance of the proposed method.

Experimental Analysis of Slender Concrete Columns at the Loss of Stability

2016 ◽  
Vol 249 ◽  
pp. 203-208
Author(s):  
Peter Kendický ◽  
Vladimír Benko ◽  
Tomáš Gúcky
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Compressive Strain ◽  
Concrete Columns ◽  
Design Methods ◽  
Critical Cross Section ◽  
Loss Of Stability ◽  
Reinforced Concrete Columns ◽  
Non Linear

The use of non-linear methods for design of slender concrete columns by European standards. For the verification of non-linear design methods it is important to compare their results with results of experiments. Within the applied research of the Faculty of Civil Engineering at Slovak University of Technology in Bratislava in cooperation with the company ZIPP Bratislava LTD the experimental verification of the slender reinforced concrete columns was realized. In the paper the authors present the preparation and process one of three series of slender reinforced concrete columns, which were made to verify the reliability of various design methods. Columns of planned second series were designed from high performance concrete C100/115, but the material tests showed that the strength class of concrete was C70/85. The columns, subjected to axial force and bending moment were designed to fail due to loss of stability before the resistance of the critical cross-section is reached. The expected compressive strain in concrete was 1,5 ‰.

Slenderness Influence on the Behavior of Composite Columns

2016 ◽  
Vol 691 ◽  
pp. 40-50
Author(s):  
Štefan Gramblička ◽  
Andrea Hrusovska
Keyword(s):  
Cross Sections ◽  
Design Method ◽  
Tall Buildings ◽  
Concrete Columns ◽  
Order Theory ◽  
Second Order ◽  
Order Effects ◽  
Composite Columns ◽  
Steel Members ◽  
Composite Steel

Composite steel and concrete columns have been used in the tall buildings due theirs high-resistance and the possibility to reduce cross sections when we compered composite columns with reinforced concrete columns. There are a lot of types of composite columns. We are concerned with columns, which are completely or partially concrete-encased steel members. In practice, a lot of composite columns are relatively slender and in design the second - order effects will usually need to be included. A partially concrete encased steel cross-section was selected for laboratory tests of composite columns. According to the results of the experiments (total of 18 columns were tested in two series), we analyzed the effects of the second - order theory. The experimental results were compared with theoretical results obtained from the model developed in the non-linear software. The evaluation of the results is also shown in comparison with the general design method according to Eurocode 4, Design of composite steel and concrete structures - Part 1.1 General rules and rules for buildings.

scholarly journals Numerical analysis of reinforced concrete shear walls with rectangular cross section

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Maurício Castelo Branco de Noronha Campos ◽  
Paulo Marcelo Vieira Ribeiro ◽  
Romilde Almeida de Oliveira
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
Second Order ◽  
Order Effects ◽  
Cross Sectional ◽  
Reinforced Concrete Columns ◽  
Mesh Model

abstract: This study addresses a numerical analysis of reinforced concrete columns in which the lengths are significantly larger than their widths with a rectangular cross section. Numerical simulations of 1,440 cases were performed, each case simulated with the single bar model, isolated bar model and mesh model, in addition, 3D model simulations were carried out. For the validation of 3D models and bar models, comparisons were made between the numerical simulation e experimental results of 24 reinforced concrete columns. Second order effects were analyzed on the vertical moment at the edge of the columns in which the lengths are significantly larger than the widths (localized second-order effects) and also the values of the horizontal moments along the cross sectional length in the mesh model. Influences of the main variables were observed influencing the behavior of the columns in which the lengths are significantly larger than their widths: the ratio between the cross sectional dimensions, the slenderness and the stresses (normal stress and bending moment around the axis of greatest inertia).

scholarly journals COMPARATIVE STUDY OF NON-LINEAR SIMULATIONS OF A REINFORCED CONCRETE SLENDER COLUMN USING FINITE ELEMENT METHOD AND P-DELTA

2019 ◽  
Vol 3 (1) ◽  
pp. 1-11
Author(s):  
Régis Marciano de Souza ◽  
Ricardo Rodrigues Magalhães ◽  
Ednilton Tavares de Andrade
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Iterative Process ◽  
Second Order ◽  
Order Effects ◽  
Non Linear ◽  
Slender Columns ◽  
Slender Column ◽  
Element Method

This paper analyzes the non-linear geometric behavior of reinforced concrete slender columns. This approach is due to the fact that there is a tendency to reinforced concrete slender constructions, which may have significant second order effects. This research aimed at comparing different formulations for the analysis of non-linear behavior of reinforced concrete slender columns by comparing results from simulated problem (slender column with ten load scenarios) between the Finite Element Method (FEM) and the Iterative Process P-DELTA(P-Δ). Numeric results revealed that the Iterative Process P-Δ presented different results from FEM and that the second order effects are significant for reinforced concrete slender column problems.

Simplified Approach Based on the Natural Period of Vibration for Considering Second-Order Effects on Reinforced Concrete Frames

2018 ◽  
Vol 18 (05) ◽  
pp. 1850074 ◽  
Author(s):  
Daniel G. Reis ◽  
Gustavo H. Siqueira ◽  
Luiz C. M. Vieira ◽  
Ronald D. Ziemian
Keyword(s):  
Reinforced Concrete ◽  
Amplification Factor ◽  
Flexible Structures ◽  
Second Order ◽  
Order Effects ◽  
Concrete Frames ◽  
Natural Period ◽  
Reinforced Concrete Frames ◽  
Order Analysis ◽  
Second Order Effects

Recent studies have demonstrated the existence of a relationship between a structures susceptibility to second-order effects and its natural period of vibration ([Formula: see text]) given that both these properties are fundamentally dependent on the structure stiffness and mass properties. The main advantage of the use of this characteristic is that [Formula: see text] can be obtained easily by the existing structural analysis software. In this study, different formulations are developed in order to propose an amplification factor ([Formula: see text]) to multiply first-order analysis results and satisfactorily obtain results of a second-order analysis. These formulations are based on D’Alembert’s principle, Rayleighs method, and the use of generalized coordinates to represent the dynamic displacement of flexible structures. It is observed that [Formula: see text] provides values closer to and in fact, more conservatively than, those obtained by the conventional simplified methods currently used by structural design engineers. Thus, the amplification factor [Formula: see text], which is based on the natural period of vibration, is proposed to be used as (i) an indicator of a structure susceptibility to second-order effects and (ii) an amplification factor to describe the second-order effects on reinforced concrete frames.

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